1. Field of the Invention
The present invention is related to sensors applied to the body of a patient for monitoring or making measurements of body tissue conditions, metabolism, or other body functions indicative of health. More specifically, the present invention is directed to a pulse oximetry sensor that can be easily applied and attached to a portion of the body of a patient in a noninvasive manner having an adhesive wrap member for use with reusable pulse oximetry sensor electronics to retain the sensor in the desired position comfortably on a patient.
2. Description of the Related Art
It is known to use a noninvasive pulse oximetry sensor to measure the relative oxygen saturation of the blood. Typically, in such oximetry sensors, a light source, such as a light emitting diode (LED), is used to alternately direct light of two different wavelengths, such as red light and infrared light, to the blood through the skin. The light transmitted or reflected by the blood at the different wavelengths can then be compared to provide a measurement of oxygen saturation of the blood.
A typical oximetry probe system contains light emitting sources, such as LEDs, and a light detector, such as a photodiode, mounted on an appendage of the body, such as a finger, toe, ear lobe, nose, hand, tongue, or foot. However, such devices need to be capable of being easily and readily attached to the body appendages, comfortable when attached to the patient, and reusable on the same patient. Additionally, such devices must be relatively inexpensive to manufacture, remain in the desired position on the patient during use without substantial movement, and fit a wide variety of patients without discomfort.
Conventional oximetry sensors use various methods to apply and retain the sensor on a patient. Such methods include, for example, mechanical clamping, deformable members, hooks and loops, adhesives and elastomeric members.
One type of oximetry sensor uses the mechanical clamping action of spring biased jaws to retain the sensor on an appendage of a patient. Such a device is illustrated in U.S. Pat. No. 4,685,464, issued to Goldberger et al. on Aug. 11, 1987, and U.S. Pat. No. 5,438,986, issued to Disch et al. on Aug. 8, 1995. While such devices are effective, they are inherently difficult to clean and inappropriate for long term use or application on a patient. Furthermore, such devices may only be used on the fingers of a patient. The clamping pressure of the spring biased jaws necessary to maintain the oximetry sensor in position on the patient's finger often is uncomfortable during long-term usage.
Another type of oximetry sensor relies upon a deformable member being located in the device to retain the sensor on an appendage of a patient. Such a device is illustrated in U.S. Pat. No. 4,865,038, issued to Rich et al. on Sep. 12, 1989 and U.S. Pat. No. 5,217,012, issued to Young et al. on Jun. 8, 1993. Because the retaining member of these types of sensors is deformed upon first use and has a memory, reinstallation of the sensor may affect the comfort of the patient during reuse.
Yet another type of pulse oximetry sensor comprises a photoemitter, a photodetector and a generally tubular housing having an inner wall, an outer wall and a lumen for receiving a body part of a patient. The housing further includes a pair of opposed pockets for removably receiving the photoemitter and the photodetector. Such a sensor is illustrated in U.S. Pat. No. 5,437,275, issued to Amundsen et al. on Aug. 1, 1995. The wrap member forming the housing comprises a wrap of a disposable material, such as paper, which may be preassembled or custom formed into the desired shape. However, such a wrap member may be used only once without deterioration thereof.
For another type of pulse oximetry sensor, a disposable optical probe includes a central portion, a pair of adhesive flanges extending from the central portion, a connector portion situated between the flanges and a pair of small adhesive flaps extending from the central portion on the end of the optical probe opposite the connector. The probe further includes a connection aperture formed in the connector portion and an emitter aperture with an emitter (e.g., a light-emitting diode) positioned within the central portion close to the connector portion. A flex pocket is located within the central portion between the emitter aperture and a detector aperture which allows light to pass through the detector aperture to a detector assembly. The probe is fabricated from multiple layers, including a flex circuit layer, a Mylar™ layer, a face stock tape layer and other tape layers. Typically, the disposable optical probe is wrapped around the end of a patient's finger during use and is secured in position by adhesive on the flaps. However, reuse of the optical probe is not typically successful because the adhesive deteriorates with each use allowing the optical probe to move.
In another instance, in an effort to facilitate reuse of a pulse oximetry sensor and to provide comfort to the patient, the sensor is retained on the finger of a patient through the use of hook and loop fabric. However, such sensors typically have used complex shapes of hook and loop fabric to retain the device thereby causing the manufacturing expense of the device to increase. Also, the sensors may need to be installed tightly on an appendage to prevent movement thereby causing discomfort for the patient. Such sensors are illustrated in U.S. Pat. No. 4,825,879, issued to Tan et al. on May 2, 1989, U. S. Pat. No. 5,209,230, issued to Swedlow et al. on May 11, 1993 and U.S. Pat. No. 5,469,845, issued to DeLonzor et al. on Nov. 28, 1995.
In another type of oximetry sensor having an adhesive, the adhesive is used to attach the sensor to an appendage of a patient in an attempt to lower manufacturing cost of the sensor, provide comfort to the patient during use of the sensor and provide a secure attachment of the sensor to the patient. However, because the sensor must often be repositioned on a patient, the adhesive loses its adhesive quality during reuse thereby allowing movement of the sensor. Also, the adhesive may irritate the patient during use, thereby causing discomfort. Such sensors are illustrated in U.S. Pat. No. 4,830,014, issued to Goodman et al. on May 16, 1989 and U.S. Pat. No. 5,170,786, issued to Thomas et al. on Dec. 15, 1992.
Again, in yet another type of oximetry sensor, an elastomeric member is used to retain the sensor on the finger of a patient. Although this allows the reuse of the sensor, the degree of pressure applied by the elastomeric member and the elastomeric member being in contact with the skin, may cause discomfort to a patient and, if too weak, may allow movement of the sensor during use. Such a sensor is illustrated in U.S. Pat. No. 5,337,744, issued to Branigan on Aug. 16, 1994.
In U.S. Pat. No. 5,999,834, entitled “Disposable adhesive wrap for use with reusable pulse oximetry sensor and method of making” (“the '834 patent”), issued to Wang on Dec. 7, 1999, a design is presented that overcomes many of the shortcomings of the conventional devices. Illustrated and described is a pulse oximetry sensor having a wrap member including a fastener, an adhesive member initially having a removable cover thereover, a release liner located thereover, an LED assembly, and a photodiode. The LED assembly and photodiode of the '834 patent are connected to a cable. In use, this sensor also may be subject to the adhesive quality being degraded by the repositioning of the sensor on an appendage of a patient or the movement of the sensor to another appendage.
Further illustrated in U.S. Pat. No. 6,256,523, issued to Diab et al. on Jul. 3, 2001 and U.S. Pat. No. 5,437,275, issued to Amundsen et al. on Aug. 1, 1995, are still other sensors having a wrap formed of multiple layers for use on an appendage of a patient.
The wraps used with the pulse oximetry sensors as discussed herein are typically located in a storeroom for respiratory equipment supplies or may be strewn about a patient's room or elsewhere. For convenience, wraps for oximetry sensors are typically packaged in bulk in a box in quantities of 100 wraps per box and, as such, are not conducive for ease of use at the point of care since a box of wraps would need to be kept in many locations of a care facility.
As discussed above, the conventional wraps or oximetry sensors are generally either reusable or expensive to manufacture, or are not easily reusable and have a relatively low manufacturing cost. Prior art wraps also may be reusable and cause discomfort to the patient. Accordingly, a pulse oximetry sensor that can be readily positioned on a patient and that is comfortable during use by a patient would be advantageous. Further, it would be desirable to manufacture a wrap that has an extended life, is reusable, has a disposable wrap member and has a low manufacturing cost.